Nicotine Modulation of Caspases in Non-Neuronal Cells

描述（由申请人提供）：虽然尼古丁对中枢神经系统（CNS）的影响被认为是最终导致成瘾的分子机制的基础，但就对外周系统的影响而言，尼古丁长期以来一直被认为是烟草中危险性较低的成分之一。在这里，我们建议重新审视这个问题，通过确定尼古丁对caspase激活外周细胞的影响。我们最近发现（Meyer，Gahring和Rogers，JBC，2002，出版中），用尼古丁预处理细胞，如在烟草制品的慢性滥用者中发生的那样，改变了半胱天冬酶8或半胱天冬酶8 - 1样蛋白酶的激活。这表明，这种基本机制可能是尼古丁如何通过其“神经元”烟碱乙酰胆碱受体（nAChR）调节免疫和炎症反应的基础，nAChR由外周细胞（包括肺上皮细胞、角质形成细胞和淋巴细胞）表达。提出的假设是：尼古丁预处理表达nAChR的细胞，如发生在慢性吸烟者中，通过破坏半胱天冬酶8激活来改变促炎和促凋亡细胞因子TNF α的信号传导。三个具体目标将解决这个假设：具体目标1。外周细胞来源的细胞系表达nAChR亚型的特定组合是否赋予尼古丁对尼古丁诱导的caspase活性的调节作用？具体目标2.尼古丁预处理是否延迟外周细胞中TNF α介导的Caspase 8激活？我们将确定是否尼古丁预处理的外周细胞改变TNFR 1或辅助蛋白的表达/组装的重要的前半胱天冬酶8的聚集和激活。具体目标3.尼古丁预处理是否改变细胞周期进程或阻碍进入尼古丁信号细胞凋亡？这些研究的意义将是定义一个可测试的模型，通过该模型，尼古丁在炎症环境中对细胞死亡易感性发挥其多效性全身效应的细胞和分子机制。

DESCRIPTION (provided by applicant): While nicotine effects on the central nervous system (CNS) are believed to underlie the molecular mechanisms that ultimately lead to addiction, in terms of effects on peripheral systems, nicotine has long been considered to be one of the less dangerous components of tobacco. Herein we propose to re-examine this issue by determining the effects of nicotine on caspase activation in peripheral cells. We have recently found (Meyer, Gahring and Rogers, JBC, 2002, in press) that pre-conditioning cells with nicotine, as occurs in chronic abusers of tobacco products, alters caspase8 or caspase8-1ike protease activation. This suggests the possibility that this basic mechanism underlies how nicotine modulates immune and inflammatory responses working through its 'neuronal' nicotinic acetylcholine receptors (nAChR) that are expressed by peripheral cells including lung epithelia, keratinocytes and lymphocytes. The hypothesis proposed is: Nicotine preconditioning of cells that express nAChRs, as occurs in a chronic smoker, alters signaling by the pro-inflammatory and pro-apoptotic cytokine, TNFalpha, through disrupting caspase8 activation. Three Specific Aims will address this hypothesis: SPECIFIC AIM 1. Does the expression of a specific combinations of nAChR subtypes by cell lines of peripheral cell origin impart nicotine regulation of cytokine-induced caspase activity? SPECIFIC AIM 2. Does nicotine pre-conditioning delay TNFalpha-mediated Caspase8 activation in peripheral cells? We will determine whether nicotine pre-conditioning of peripheral cells alters the expression/assembly of TNFR1 or auxiliary proteins important for pro-caspase8 aggregation and activation. SPECIFIC AIM 3. Does nicotine pre-conditioning alter cell cycle progression or impede entry into cytokine-signaled apoptosis? The implications of these studies will be to define a testable model with regard to the cellular and molecular mechanisms through which nicotine exerts its pleiotropic systemic effects on cell susceptibility to death in the milieu of an inflammatory environment.